Sleep Deprivation Delays Oral Ulcer Healing Via Netosis

The impact of disturbed sleep on oral ulcer (OU) is well known but the immunological mechanism remains little discovered. This study was approved by the Laboratory Animal Welfare and Ethics Committee. Eight-week-old healthy C57BL/6 female mice were used to establish OU and OU+SD model. In this study, we show that sleep deprivation (SD) substantially hindered mucosa healing and epithelial migration in a mice model with chemically injured OU and induced excessive neutrophil extracellular traps (NETs) collocated with epithelial layers. NETs deficient PAD4-/- mice, mice treated with anti-Ly6G showed faster healing rate under sleep deprivation rather than their WT counterparts. Mouse bone marrow derived neutrophils isolated from SD mice exhibited higher level of NETs with and without PMA stimulation. Isolated NETs hampered the migration but not viability, or apoptosis of HACAT cells. Using a series of pharmacological inhibitors and therapeutic antibodies, we found neutrophil elastase (Elane) rather than MPO, MMPs, histones, or DNA backbones mostly contributes to the negative impact of NETs on HACATs migration and cell-cell junction. NETs and recombinant Elane effectively lowered the expression of ZO-1, Claudin-5, and their complex, but not E-Cadherin, Claudin-1, or Occludin in HACATs. Elane inhibitor sivelestat, promoted OU healing, ZO-1/Claudin-5 expression and epithelial migration in sleep deprived mice. Collectively, our study found excessive NETs as an immunological pathology in OU mice with SD and suggests Elane as a potential treatment target for OU patients with bad sleep.